Refrigerator

ABSTRACT

Provided is a refrigerator including: at least one temperature sensor; a memory storing controls for a plurality of levels; and a processor selecting a control, from among the controls, based on a temperature measured by the temperature sensor.

TECHNICAL FIELD

The present invention relates to a technique directed to refrigeratorsand, in particular, to a technique for efficiently controlling therefrigerators.

BACKGROUND ART

A typical refrigerator includes a compartment temperature sensormeasuring a compartment temperature of the refrigerator. Therefrigerator starts a cooling operation when the temperature measured bythe compartment temperature sensor rises above a first predeterminedtemperature (e.g., 4° C.), and suspends the cooling operation when thetemperature measured by the compartment temperature sensor falls belowthe first predetermined temperature (e.g., 3° C.).

CITATION LIST Patent Literature

[Patent Document 1] Japanese Unexamined Patent Application PublicationNo. H01-234781

SUMMARY OF INVENTION Technical Problem

Unfortunately, the above configuration might either excessively cool, ornot be able to appropriately cool, the compartment of the refrigeratoras illustrated in FIG. 19, depending on positions of the compartmenttemperature sensor and of foods and beverages newly placed in therefrigerator.

Specifically, when a not-cold object; that is, for example, a cannedbeverage brought close to a warm room temperature, is placed near thecompartment temperature sensor, the temperature measured by thecompartment temperature sensor rises inevitably high. Hence, a placeaway from the canned beverage is highly likely to be cooled more thannecessary. In contrast, when a cold canned beverage is placed near thecompartment temperature sensor, the temperature measured by thecompartment temperature sensor falls inevitably low even if a not-coldfood or beverage is put somewhere else. Hence, the temperature of aplace away from the place of the cold canned beverage could exceed atemperature appropriate for the food and beverage.

In order to address those problems, Patent Document 1 discloses atechnique to forcefully suspend cooling a refrigerated room if therefrigerated room is cooled for a predetermined time period or longer toprevent the refrigerated room from being overcooled. However, such anovercooling prevention technique, which merely involves forcefullysuspending cooling in the predetermined time period, is difficult toapply to foods and beverages that the refrigerator stores in variousstates. Moreover, the above technique is not applicable to acountermeasure to insufficient cooling.

Solution to Problem

A refrigerator according to an aspect of the present invention includes:at least one temperature sensor; a memory storing controls for aplurality of levels; and a processor selecting a control, from among thecontrols, based on a temperature measured by the temperature sensor.

Advantageous Effects of Invention

The present invention provides a refrigerator capable of efficientcontrol over various storage conditions.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional side view illustrating a typicalrefrigerator.

FIG. 2 is a graph illustrating variation in compartment temperatureaccording to a first embodiment.

FIG. 3 is a block diagram illustrating a structure of a refrigerator 100according to the first embodiment.

FIG. 4 is a block diagram illustrating an operation level table 121according to the first embodiment.

FIG. 5 is a flowchart illustrating control processing according to thefirst embodiment.

FIG. 6 is a flowchart illustrating processing for setting an operationlevel according to the first embodiment.

FIG. 7 is a flowchart illustrating processing for setting an operationlevel according to a second embodiment.

FIG. 8 is a block diagram illustrating an operation level table 122according to a third embodiment.

FIG. 9 is a flowchart illustrating control processing according to thethird embodiment.

FIG. 10 is a flowchart illustrating processing for setting an operationlevel according to the third embodiment.

FIG. 11 is a graph illustrating a first variation in compartmenttemperature according to the third embodiment.

FIG. 12 is a block diagram illustrating an operation level table 122after a first user-adjustment according to the third embodiment.

FIG. 13 is a graph showing a first variation in compartment temperatureaccording to a fourth embodiment.

FIG. 14 is a graph showing a second variation in compartment temperatureaccording to a fifth embodiment.

FIG. 15 is a block diagram illustrating an operation level table 123according to a sixth embodiment.

FIG. 16 is a flowchart illustrating processing for setting an operationlevel according to the sixth embodiment.

FIG. 17 is a flowchart illustrating sensor canceling processingaccording to a seventh embodiment.

FIG. 18 is a flowchart illustrating sensor cancelling processingaccording to an eighth embodiment.

FIG. 19 is a graph showing a variation in compartment temperature of atypical refrigerator.

DESCRIPTION OF EMBODIMENTS

Described below are the embodiments of the present invention, withreference to the drawings. In the detailed description that follows,identical constituent features have the same reference numerals. Suchconstituent features have the same name and function, and the detailsthereof will not be repeatedly elaborated upon.

First Embodiment

Configuration of Refrigerator

First, a technique according to this embodiment is applicable to atypical refrigerator 100 illustrated in FIG. 1. The technique isapplicable to, for example, a refrigerator including a refrigeratorcompartment and a freezer compartment, a refrigerator including arefrigerator compartment alone, and a refrigerator including a vegetablecompartment and a chilling compartment.

The refrigerator according to this embodiment is directed to effectiveuse of foods, beverages, and compartment air of the refrigerator whichhave already been cooled, while avoiding excessive influence of foodsand beverages newly stored in the refrigerator. As illustrated in FIG.2, for example, a refrigerator basically repeats a cooling operationbased on a level selected from among multiple stages of level settings.The refrigerator repeats such an operation previously programmed. Hence,even if an object having a large heat capacity is placed near acompartment temperature sensor, the refrigerator can reduce the riskthat the compartment temperature of the refrigerator excessively risesor falls.

Furthermore, the refrigerator sets an upper limit of the compartmenttemperature of the refrigerator higher (e.g., 10° C.) than usual, and alower limit of the compartment temperature of the refrigerator lower(e.g., 1° C.) than usual. Based on the compartment temperature of therefrigerator, the refrigerator controls a compressor and a damper. Thus,as illustrated in FIG. 2, for example, when new foods and beverages areplaced near the compartment temperature sensor at approximately fouro'clock in the morning, the refrigerator continues the cooling operationregardless of the program setting until approximately five twenty in themorning at which the temperature of the compartment temperature sensorfalls below the upper limit (10° C.). Moreover, although not shown, therefrigerator can suspend the cooling operation regardless of the programsetting when the temperature of the compartment temperature sensor fallsbelow the lower limit.

Hence, with basic cooling performed in the previously programmedoperation, the compartment temperature sensor is additionally used toreduce the risk of excessive rise and fall of the compartmenttemperature of the refrigerator while avoiding over-control.

Furthermore, the refrigerator according to this embodiment (i) sets thelevel setting for cooling the compartment of the refrigerator high if atemperature of the compartment temperature sensor is higher than theupper limit at a predetermined time point, and, on the contrary, (ii)sets the level setting for cooling the compartment of the refrigeratorlow if the temperature of the compartment temperature sensor is lowerthan the lower limit at a predetermined time point. Such features makeit possible to appropriately select a cooling level for various storageconditions in the refrigerator, reducing the risk that the compartmenttemperature of the refrigerator excessively rises or falls.

As illustrated in FIG. 3, the refrigerator 100 according to thisembodiment mainly includes, for example: a central processing unit (CPU)110 mounted on a control board; a memory 120; a display 130 fordisplaying various kinds of text and images in response to a signal fromthe CPU 110; a controller 140 receiving various commands from a user; atimer 150 measuring an elapsed time period from a time and apredetermined time point; a compressor 160; a fan 170; a damper 180; acompartment temperature sensor 191; and an ambient temperature sensor192.

The memory 120 according to this embodiment stores an upper-limittemperature (e.g., 10° C.) and a lower-limit temperature (e.g., 1° C.)of the compartment temperature sensor 191 in the refrigeratorcompartment. Moreover, the memory 120 stores an operation level table121 as illustrated in FIG. 4. The operation level table 121 according tothis embodiment stores a combination of a cooling-ON time period and acooling-OFF time period for each of the operation levels.

Note that, the operation level table 121 shall not be limited to theabove configuration. Alternatively, as described later, the operationlevel table 121 may store, for each operation level, a rotation speed ofthe compressor 160, a rotation speed of the fan 170, and a combinationof the rotations speeds.

Processing by Controller

In this embodiment, the refrigerator 100 executes processing illustratedin FIG. 5. Note that FIG. 5 is a flowchart illustrating how the CPU 110according to this embodiment processes information.

When a power supply turns ON, the CPU 110 reads an ON time period and anOFF time period, of a set operation level, from the operation leveltable 121, sets the compressor 160, the fan 170, and the damper 180 forthe ON time period and the OFF time period as an ON time-period timerand an OFF time-period timer, and starts to measure the OFF time period(Step S102).

With reference to the timer 150, the CPU 110 determines whether the OFFtime-period timer reaches a set value (Step S104).

If the OFF time-period timer reaches the set value (Step S104: YES), theCPU 110 sets an operation level (Step S108). In this embodiment, theprevious operation level is stored in the memory 120. The CPU 110executes operation level setting processing to be described later basedon the previous operation level, and sets a current operation level. Theoperation level setting processing will be described later. Note that,the previous operation level in a factory setting may be an intermediateoperation level to be preliminarily set.

Based on the current operation level, the CPU 110 causes the compressor160, the fan 170, and the damper 180 to start the cooling operation inaccordance with the operation level table 121 (Step S110). The CPU 110starts measuring the ON time period (Step S112). The CPU 110 determineswhether a cooling end condition is met (Step S114). In this embodiment,the CPU 110 determines that the cooling end condition is met if the ONtime-period timer determines that a set stand-by period has passed, anda temperature measured by the compartment temperature sensor 191 is apredetermined upper limit temperature of, for example, 10° C. or below.

If the cooling end condition is met (Step S114: YES), the CPU 110suspends the cooling operation of the compressor 160, the fan 170, andthe damper 180 (Step S116). The CPU 110 starts the OFF time-period timer(Step S118).

Described next is the operation level setting processing in Step S108 ofFIG. 5. FIG. 6 is a flowchart illustrating the operation level settingprocessing executed by the CPU 110.

With reference to FIG. 6, the CPU 110 determines whether anoperation-level-down condition is satisfied (Step S1081). Here, the CPU110 determines that the operation-level-down condition is satisfied whenthe temperature, measured by the compartment temperature sensor 191 atthe suspension of the previous cooling operation (Step S116), is apredetermined lower limit temperature of, for example, 1° C. or below.If the operation-level-down condition is satisfied (Step S1081: YES),the CPU 110 determines that the refrigerator 100 is overcooled, andturns down the operation level for one stage (Step S1082).

The CPU 110 further determines whether an operation-level-up conditionis satisfied (Step S1083). Here, the CPU 110 determines that theoperation-level-up condition is satisfied when a current temperature;that is, the temperature measured by the compartment temperature sensor191 at the start of the current cooling operation (Step S108) is thepredetermined upper limit temperature of, for example, 10° C. or above.If the operation-level-up condition is satisfied (Step S1083: YES), theCPU 110 determines that the refrigerator 100 is not sufficiently cooled,and turns up the operation level for one stage (Step S1084). The CPU 110proceeds to the processing in Step S110 of FIG. 5.

Hence, the cooling operation in this embodiment is not sequentiallycontrolled with the value measured by the compartment temperature sensor191. Alternatively, with basic cooling performed on a previouslyprogrammed operation setting, the cooling operation is controlled andthe operation level settings are changed based on the upper limittemperature, the lower limit temperature, and the compartmenttemperature at a predetermined time point. Such features make itpossible to execute efficient control while avoiding over-control.

Second Embodiment

Note that the operation level setting processing shall not be limited tothe one in the above embodiment. For example, as illustrated in FIG. 7,if the operation-level-down condition is satisfied (Step S1081: YES),the CPU 110 may turn the operation level down for one stage (StepS1082), omitting determination of the operation-level-up condition. Incontrast, though not illustrated, if the operation-level-up condition issatisfied (Step S1083: YES), the CPU 110 may turn the operation level upfor one stage (Step S1084), omitting determination of theoperation-level-down condition.

Third Embodiment

The operation level setting processing may further involve determiningan operation level based on an ambient temperature of the refrigerator100. In this case, the memory 120 stores an operation level table 122 asillustrated in FIG. 8. The operation level table 122 according to thisembodiment stores, for each of the operation levels, a correspondingrelationship between a condition of an ambient temperature of therefrigerator 100, a cooling-ON time period, and a cooling-OFF timeperiod.

In this embodiment, as illustrated in FIG. 9, if the OFF time-periodtimer reaches the set value (Step S104: YES), the CPU 110 obtains fromthe ambient temperature sensor 192 an ambient temperature of therefrigerator 100 (Step S106). The ambient temperature of therefrigerator 100 measured by the ambient temperature sensor 192 isobtained immediately before the compressor 160 starts the coolingoperation. Such a feature allows the operation level setting processingto be less likely affected by a variation in the ambient temperature ofthe refrigerator 100 caused by the cooling operation, such as by heatfrom the compressor 160.

Then, as shown in Step S108 of FIG. 10, the CPU 110 identifies anoperation level, based on a temperature measured by the ambienttemperature sensor 192, with reference to the operation level table 122.Then, in Step S110, the CPU 110 causes the compressor 160, the fan 170,and the damper 180 to start cooling operation, based on the identifiedoperation level, with reference to the operation level table 122.

Such features make it possible to reduce the risk that the compartmenttemperature of the refrigerator 100 excessively rises or falls becauseof a variation in the ambient temperature of the refrigerator 100 asillustrated, for example, in FIG. 11. Moreover, even if the valuemeasured by the compartment temperature sensor rapidly rises because newfoods and beverages are placed in the refrigerator at approximately fouro'clock in the morning (see FIG. 11), the cooling operation iscontrolled, based on the identified operation level, with reference tothe operation level table 122 as seen in the first embodiment. Such afeature makes it possible to reduce the risk, and the degree, that thecompartment temperature excessively rises or falls.

Furthermore, the refrigerator 100 may allow a determination criterion ofthe operation levels to be customized by a user through the controller140. For example, the CPU 110 may receive a setting command to uniformlyraise by 2° C. a condition of the ambient temperature of therefrigerator 100 for each operation level, and store information on thesetting command in the memory 120 as illustrated in FIG. 12. Such afeature allows the user to set the compartment temperature of therefrigerator to a desired one. For example, as described above, if theuser provides a setting command to uniformly raise by 2° C. a conditionof the ambient temperature of the refrigerator 100 for each operationlevel, the compartment temperature of the refrigerator can be raised byapproximately 1° C.

Note that, here, the CPU 110 utilizes data measured by the ambienttemperature sensor 192 to determine the most suitable of all theoperation levels. Alternatively, the CPU 110 may utilize data measuredby the compartment temperature sensor 191 to determine the most suitableof all the operation levels.

Fourth Embodiment

The operation level settings in the above embodiments may be combinedtogether. In the operation level setting processing (Step S108), the CPU110 may provisionally determine an operation level with the processingin FIG. 10, and then increase or decrease the operation level with theprocessing in FIGS. 6 and 7.

More specifically, as illustrated in FIG. 13, an operation level of fouris determined based on the ambient temperature of the refrigerator 100between five o'clock and six o'clock in the morning. At the start of thecurrent cooling operation, the operation-level-up condition is met.Hence, the CPU 110 corrects the operation level to read five.Furthermore, an operation level of five is determined based on theambient temperature of the refrigerator 100 between three o'clock andfour o'clock in the afternoon. At the end of the previous coolingoperation, the operation-level-down condition is met. Hence, the CPU 110corrects the operation level to read four.

Moreover, an operation level of four is determined based on the ambienttemperature of the refrigerator 100 between four o'clock and fiveo'clock in the morning. At the end of the previous cooling operation,the operation-level-down condition is met. However, theoperation-level-up condition is met at the start of the current coolingoperation. Hence, the CPU 110 determines the operation level to readfour.

Fifth Embodiment

Note that, if a temperature of the compartment temperature sensor oncerises above the upper limit temperature as illustrated in FIG. 14, theCPU 110 may allow the refrigerator 100 to continue the cooling operationuntil the rising temperature falls below the lower limit temperature.

Sixth Embodiment

Moreover, an operation level to be set may include an open-close controlof a damper and a rotation speed of a compressor. As illustrated in FIG.15, for example, the operation level table 123 in this embodimentstores, for each operation level, a corresponding relationship between acondition of an ambient temperature of the refrigerator 100, a damperopening time period, a compressor-ON time period, a compressor-OFF timeperiod, a rotation speed of the compressor in a normal condition, and arotation speed of the compressor after defrost.

As illustrated in FIG. 16, the CPU 110 in this embodiment determines,with reference to the timer 150, whether the OFF time-period timerreaches a set value (Step S104).

If the OFF time-period timer determines that a set cooling period haspassed (Step S104: YES), the CPU 110 obtains from the ambienttemperature sensor 192 an ambient temperature of the refrigerator 100(Step S106).

The CPU 110 sets an operation level based on the operation level table123 and results of measurement by various sensors (Step S108).

As the cooling operation processing (Step S110), the CPU 110 causes thecompressor 160 to start operating (Step S1100). Here, the CPU 110determines a rotation speed of the compressor 160 with reference to theoperation level table 123. The CPU 110 starts an ON timer of thecompressor 160 (Step S1101). The CPU 110 opens a damper (Step S1102).The CPU 110 starts a damper-open timer (Step S1103).

With reference to the operation level table 123, the CPU 110 determineswhether the damper-open timer reaches a set value (Step S1104). If thedamper-open timer reaches the set value (Step S1104: YES), the CPU 110closes the damper (Step S1105).

With reference to the operation level table 123, the CPU 110 determineswhether the compressor-ON timer reaches a set value (Step S1106). If thecompressor-ON timer reaches the set value (Step S1106: YES), the CPU 110suspends the operation of the compressor 160 (Step S1107).

The CPU 110 determines whether a defrost condition is satisfied (StepS1108). If the defrost condition is satisfied (Step S1108: YES), the CPU110 performs a defrost operation (Step S1109). When the defrostoperation ends, the CPU 110 starts the OFF time-period timer (StepS118).

Note that, as shown in FIG. 15, the temperature of the freezercompartment is expected to rise after the end of the defrost operation.Hence, the rotation speed of the compressor may be set higher thanusual. Furthermore, the OFF time-period timer may be set shorter thanusual.

Seventh Embodiment

In addition to the above embodiments, the refrigerator 100 may include amode to cancel the compartment temperature sensor 191. Canceling thesensor specifically means that the communication between the sensor andthe CPU 110, or the power to be supplied to the sensor, is shut down. Inmany cases, the compartment temperature sensor 191 is connected notthrough the control board but through the wiring. Moreover, thecompartment temperature sensor 191 is exposed to an environment in whichtemperature and humidity significantly vary. That is why the compartmenttemperature sensor 191 have more reasons to fail than an elementsoldered on the control board does. Hence, through the controller 140,the refrigerator 100 according to this embodiment receives a command totransit to a mode to cancel the compartment temperature sensor 191; thatis, a command to transit to, for example, a first service mode.Alternatively, the CPU 110 may determine whether the compartmenttemperature sensor 191 is in failure, based on data measured by thecompartment temperature sensor 191. If the CPU 110 determines that thecompartment temperature sensor 191 is in failure, the refrigerator 100may transit to the first service mode to cancel the compartmenttemperature sensor 191. In this case, the refrigerator 100 may include adisplay mechanism to notify the user of the transition to the servicemode.

For example, as shown in FIG. 17, when receiving the command to transitto the first service mode, the CPU 110 shuts down the communicationwith, or the power supply to, the compartment temperature sensor 191(Step S302). Then, when receiving a command to finish the first servicemode (Step S304: YES), the CPU 110 restores the communication with, orthe power supply to, the compartment temperature sensor 191 (Step S306).

Note that while, the refrigerator 100 is on the first service mode, theCPU 110 does not make determination on the upper limit value or thelower limit value in the cooling end condition of S114.

Eighth Embodiment

Alternatively, in addition to the above embodiments, the refrigerator100 may include a mode to cancel the ambient temperature sensor 192.Through the controller 140, the refrigerator 100 according to thisembodiment receives a command to transit to a mode to cancel the ambienttemperature sensor 192 and the compartment temperature sensor 191; thatis, a command to transit to, for example, a second service mode.Alternatively, the CPU 110 may determine whether the ambient temperaturesensor 192 is in failure, based on data measured by the ambienttemperature sensor 192. If the CPU 110 determines that the ambienttemperature sensor 192 is in failure, the refrigerator 100 may transitto the second service mode to cancel the ambient temperature sensor 192and the compartment temperature sensor 191. Note that the second servicemode may involve canceling the ambient temperature sensor 192 andmaintaining the communication between the CPU 110 and the compartmenttemperature sensor 191.

In this embodiment, the CPU 110 may preferably cause the memory 120 tostore a temperature measured by the ambient temperature sensor 192. Forexample, the memory 120 may store the latest temperature measured, orthe highest temperature measured for the last 24 hours, or the averagetemperature measured for the last 24 hours. In addition, the ambienttemperature of the refrigerator 100 may be obtained from the server lasttime. Alternatively, a predicted ambient temperature previously obtainedfrom the server is used as the ambient temperature of the refrigerator100. In this case, the ambient temperature to be obtained from theserver may be an ambient temperature measured by another electricappliance placed near the refrigerator 100, or a temperature, of an areain which the refrigerator 100 is installed, to be obtained through theInternet.

Hence, as shown in FIG. 18, when receiving the command to transit to thesecond service mode, the CPU 110 shuts down the communication with, orthe power supply to, the ambient temperature sensor 192 and thecompartment temperature sensor 191 (Step S402).

With reference to the timer 150, the CPU 110 determines whether the OFFtime-period timer reaches a set value (Step S404).

If the OFF time-period timer determines that a set cooling time periodhas passed (Step S404: YES), the CPU 110 obtains from the memory 120 apreviously obtained ambient temperature of the refrigerator 100 (StepS406).

The CPU 110 sets an operation level (Step S108). The processingsucceeding the setting of the operation level is identical orsubstantially identical to that in the above embodiments, and thereforewill not be repeated.

Such features make it possible to prevent the refrigerator 10 fromperforming an abnormal cooling operation even if the compartmenttemperature sensor 191 and the ambient temperature sensor 192 are infailure. Moreover, the operation level is set with a temperaturerecently measured by an ambient temperature sensor. Hence, even in aperiod in which a temperature sensor is not available, the compartmenttemperature can be maintained at an appropriate temperature.

SUMMARY

Provided in the above embodiments is the refrigerator 100 including: atleast one temperature sensor 191, 192; a memory 120 storing controls fora plurality of levels; and a processor 110 selecting a control, fromamong the controls, based on a temperature measured by the temperaturesensor 191, 192.

Preferably, the at least one temperature sensor 191, 192 may include afirst sensor configured to measure a compartment temperature of therefrigerator. The processor 110 may select a control, from among thecontrols, for a high level if the temperature of the compartmenttemperature sensor 191 rises above an upper limit, and to select acontrol, from among the controls, for a low level if the temperature ofthe compartment temperature sensor 191 falls below a lower limit, thehigh level and the low level being included in the levels.

Preferably, processor 110 may continue a cooling operation until thetemperature of the compartment temperature sensor 191 falls below theupper limit.

When receiving a command to designate a first mode, the processor 110may cancel the selection of the controls for the upper limit and thelower limit.

Preferably, the at least one temperature sensor 191, 192 may include asecond sensor measuring an ambient temperature of the refrigerator 100.The processor 110 may select the control based on a past ambienttemperature of the refrigerator 100.

Preferably, when receiving a command to designate a second mode, theprocessor 110 may select the control based on a past ambient temperatureof the refrigerator 100.

The embodiments disclosed herewith are examples in all respects, andshall not be interpreted to be limitative. The scope of the presentinvention is intended to be disclosed not in the above embodiments, butin the claims. All the modifications equivalent to the features of, andwithin the scope of, the claims are to be included in the scope of thepresent invention. Moreover, a configuration may be obtained from acombination of the configurations of different embodiments described inthis Description. Such a configuration is also included within the scopeof the present invention.

REFERENCE SIGNS LIST

-   100: Refrigerator-   110: CPU-   120: Memory-   121: Operation Level Table-   122: Operation Level Table-   123: Operation Level Table-   130: Display-   140: Controller-   150: Timer-   160: Compressor-   170: Fan-   180: Damper-   191: Compartment Temperature Sensor-   192: Ambient Temperature Sensor

1. A refrigerator comprising: at least one temperature sensor; a memorystoring controls each corresponding to one of a plurality of coolingoperation levels; and a processor configured to select a control, fromamong the controls, based on a temperature measured by the temperaturesensor.
 2. The refrigerator according to claim 1, wherein the at leastone temperature sensor includes a first sensor configured to measure acompartment temperature of the refrigerator, and the processor isconfigured to select, from among the controls, a control for a coolingoperation level higher than a previously selected cooling operationlevel if the compartment temperature rises above an upper limit, and toselect, from among the controls, a control for a cooling operation levellower than a previously selected cooling operation level if thecompartment temperature falls below a lower limit, the high level andthe low level being included in the levels, the cooling operation levelsand the previously selected cooling operation levels being included inthe plurality of cooling operation levels.
 3. The refrigerator accordingto claim 2, wherein the processor is configured to continue a coolingoperation until the compartment temperature falls below the upper limit.4. The refrigerator according to claim 2, wherein when receiving acommand to designate a first mode, the processor is configured to cancelthe selection of the controls for the upper limit and the lower limit.5. The refrigerator according to claim 1, wherein the at least onetemperature sensor includes a second sensor configured to measure aambient temperature of the refrigerator, and the processor is configuredto select the control based on the ambient temperature of therefrigerator.
 6. The refrigerator according to claim 5, wherein whenreceiving a command to designate a second mode, the processor isconfigured to select the control based on a past ambient temperature ofthe refrigerator.